1. (

• compaction ,
• compression ,
• concretion ,
• densification

) an increase in the density of something ;

2. (

• compression ,
• condensation ,
• contraction ,

) the process or result of becoming smaller or pressed together; "the contraction of a gas on cooling" ;

3. (

• compression ,

) encoding information while reducing the bandwidth or bits required ;

4. (

• compression ,
• compressing

) applying pressure ;